US2982323A - Coiled spring washer having coils bearing opposed vertices and troughs - Google Patents

Description

May 2, 1961 F. K. VOSSLOH ETAL 2,982,323

comm SPRING WASHER HAVING cons BEARING OPPOSED VERTICES AND TROUGHS Filed April 10, 1956 Fag.

INVENTORS FRIEDRICH KARL. VOSSLOH F HERMANN MEIER ATTORNEY The invention relates to-a coiled spring washerof the type-described in my co-pending application f or;,;U S.' Patent; Serial Number 229,314, filed-June 1,1951, now abandoned, and of which this application is acontinua tion in 'part. Washers of the type heTe-undenconsidera-- tion are useful for many-purposes, and especially, as l oclcing washers for nuts in r'ailroad superstructure construca tion. A- conventional washerfor that purpose is a spring consisting of a wire of rectangularLcross-sectio coiled into two helical convolutions which arercrimped wave like out of the line of the basic helix, In such a conven; tional washer the maximum length of the basis of the crimp of each convolution equals the outendiametenoi the. washer corresponding to a distance of, 18 of the, end points of a crimp from each other. U1l t1 el. CQl1 1 pression the convolutions willfirst comeflqjbear upon each other with the free ends, the deflectionbeing similar to that of a corresponding normal spring. A'further ini crease of the load will then flatten thecrimped er -arched, portions, a relatively much higher loadv being required.

for such. flattening thanforthe. deformation of the basic Patented May 2, 1961 2 V a convolution, and wherein the end points of each crimp are spaced appreciably more than 180, preferably between- 240 and 270. 7 p

A washer according to the invention has a portion of the middle convolution sowave-like crimped that there is a crestvertex and a trough vertex at opposite sides of and equally spacedfrom the mid-length point ofthe middle convolution, and the remaining portions of the middle convolution and the adjoining end convolutions being so wave-like bent that there are points of potential initial contact, one diametrically opposite the mid-length '1 point and one between each vertex'and the end portion of the adjacent end convolution.

Further objects and details of the invention will be apparent fromthe description given hereinafter and the accompanying drawing illustrating an embodiment there! of by wayof example. I Y

In the drawing: -Fig. l is a, top plan view of a washer according to the invention,

Fig. 2 is a ont, elevation of the washer of Fig. 1, Fig.3,is a rear view, I Fig. 4-is a side elevation, and Figs. 5 and 6 are developed views of the washer at zero load and high load, respectively. j Referring now to the drawing, the washer is coiled of wire and comprises a middle convolution 10 and an upper.

and a lower' end convolution 11 and 12, respectively.

Although Figs. l-to 4 clearly show the washer according to the invention, Figs. 5 and 6 are added to facilitate the" understanding of the shape and the operation thereof;

helix. Hence, while e.g. in acer'tainkindjof: cohvem} J tionalwashers of the :mentionedtypea load of lOilolkilo grams causes a deflectiongi e a reduction-of the axial length of the .washer of about,4. 7.,millimeters,an'increase;

of the load from 1000 to .3000. kilograms causes aheflecef tion of merely.6 millimeter.

Now it has been found that such rate of deflectionin;

the higher range of compression is undesirablylsmall."

If it is assumed that such a conventionalwasher'is used in a screw connection, suchsas in. a railroadysupers'tr'ucr ture wherethe bearing surfaces ofitheconncted parts are subject to intense wear, and'thanoriginally theco ni' nection was so tightened as to compress the washerirwithi will reduce the. compression to.v l00tlfkilograrnsand fwill' correspondingly lower the. locking .e' ifect of the. washer. The invention aims to avoid this drawback fandlo p'romentioned conventional type.

a coil and a complete coil wherein the convolution's are wave-like crimped or arched out of the line ofthe helix and form three potential contact points betwee'ntheconvolutions, one of said points being located diametrically opposite the mid-length point of the middle convolution and the other two points are located near the free ends;

respectively, of the end convolutions.

Another object of the invention is the, provision of a washer of the mentioned type, wherein the middle convolution is crimped to form a wave andthe endlcon-yolutions, are so crimped as to form a wave crest in registry witha wave trough of the middle convolution, and also a wave trough in registry with a wave crest of the middle- In these figures, which are developments of the washer, the total length of each figure corresponds to one com--- plete convolution of 360" and the figure is obtained'by visualizing a sec-tion in an axial plane-thr'ough the middle; convolution at equal distances of the ultimate'endsfof; the upper and lower convolutionsthat means inan axialplane from a to b in Fig.- 1; he. through points-B5B" in Fig. 3, then, spreading the three convolutions sothat themiddle convolution extends from E to E in the position of Fig. 5,.andfinallyarrangingthe spread upper and lower convolutions in their correct relativepositions in respect to the middle convolution 'An imaginary view of a complete. development ofthe peripheral surface of; the Whole washer can be obtained by' visualizing the upper convolution with its right hand end in Fig? 5 -atf tached to the left hand end of the middle convolution and" the'left hand end of the lower convolution attached to 'the rightlhand end of the middle'convolution. 1 Hence;

both ends of Figs. "5 and 6 are located onthe same s'ec I tional plane of the spring washer. In Fig. 5, the'w'asher each a length of about 315.

is not loaded, whereas in Fig- 6 it is assumed that the washer is under a load of 3000 kilograms corresponding tothat of the conventional'washer mentioned h'erei'nbe-{ fore. .In'the illustrated embodiment, the middle con'volu'f tion has a total length of 360 and the end convolutions The convolution sare crimped or bowed out of the linebf the helix h according to which the wire, of rectangular cross-section; is"? coiled. This cross-section is visible at the ends 1-3fa'nd' 14 in Fig. 3, whereas some points of the helix'areindicated in Fig; 5 by intersection dot and dash lines.

clearly shown in Figs. Z'and 5, the middle convolutionis so bent as to form a wave with a crest .15 having a' vertex A and a trough 16 having a vertex B. The vertices A and B are equally spaced from the mid-length point 0'.

i In Fig. 1 the radii onwhich the points A and- B are located have the reference charactersA and-B respectively; they are spaced from each other. The wave extends between the axial: plane indicated by the lines :6.

and D. It will be'noted that the wave portions 5 (71 need not be equal to the portions and fact, it is preferred that the first mentioned portions are longerthan the last mentioned ones. Diametrically opposite the mid-length point 0, the end points of the middle convolution are denoted by E and E' in Figs. 3, 5 and 6. The portion CE with-the adjoining upper endconvolution, and the portion DE with the adjoining lower end convolution are also Wave-like bowed out of the lineof the helix h in such a manner that points E and E are rather close to each other, and that the upper end convolution forms a crest 17 with vertex F in registry with the vertex B of the middle convolution and has a point G in registry with and'in very close proximity to the point A. It will be noticed that the spacing between the upper end and the middle convolutions increases very gradually from point G to point H, which is in registry with the midlength point 0, whereas the spacing increases at an ap preciably higher rate in the portion between points H and F. Similarly, the lower end convolution has a trough 18 with vertex I in registry with the vertex A, a point K in registry with the mid-length point 0, and a point'L in registry with and in close proximity to point .B. The ultimate end portions 19 and 20, which extend in the upper end convolution between 13 and G and in the lower end convolution between 14 and L, respectively, are approxi mately as close to the middle convolution as the points G and L. Now it will be seen that the arched portion G? of the upper end convolution and the portion E A of the middle convolution registering with Ci E extend each 180 plus the distance E Similarly, the lower portions points G and L, where the inner ends of the ultimate end portions 19 and 20 bear on the middle convolution, will travel towards each other and finally, when the washer is under full load as in Fig. 6, reach the points G and L', respectively. The pressure points E, E, however, will not change their position. Hence, in the illustrated embodiment, the original supporting bases for the arched portions of the washer extend from point B to point G for the upper, and from point E to L for the lower convolution, i.e. 255 for each, and decreases under full load so as to extend from E to G' and from E to L', i.e. approximately 200. The fact that each supporting base extends from a point opposite the midlength point to a Wave line vertex circumferentially beyond the mid-length point ensures, in all instances, a base length of more than 180, which is necessary in order to obtain a particularly'large, highly durable spring movement in the high tension range.

E 'I and El? extend 180 plus 61 3. In'other words, the

effective arched portions of the upper and lower convolutions have each a length of 180 plus the spacing of one of the vertices A and B from the midlength point 0. Purely from the theoretical view point, the point A, for instance, may be located anywhere between the point 0 and the pointE. Of course, the portions 19 and 20 must always be so far extended that there may be a point G in registry with A and a point L in registry with B. It follows, that in a three-coil washer of a design according to our invention, the basis of the arched portions must extend not less than 180 and not more than 360. In practice, however, in order to avoid too steep an inclination of a portion of the washer, the vertex A, and thus, also the vertex B, should be spaced from the mid-length point between about 60 to 90, which results in a base length of the arched portions of between 240 and 270. We have found that a 75 spacing of the mentioned vertices from the point 0 gives very satisfactory results. The length of the portions 19 and 20 can be selected rather freely. They serve, on the one hand, as an elongated support to transmit the load to the middle convolution, as hereinafter explained. On the other hand, they are destined, together with the points F and I, to receive the load from the outside. include points M and N coplanar with the points F and I, respectively. In Fig. 5 they are shown, in their preferred location, as spaced about 180 fromeach other. But they may be located anywhere on the outside of the portions 19 and 20.

Owing to the described structure of the washer, the points A, G; B, L; and E, E are potential contact points at zero load. When the spring washer is in use, points A, G and B, L and the end portions 19 and 20 make contact with the adjacent portions of the middle convolution practically immediately when a compressive force is applied at M and F with reaction at N and I. Shortly thereafter, when the compression increases but is still in the range of a relatively small load, the points E and E will contact each other as the washer deflects in the manner of a normal helical spring. When the compression further increases, the bowed portions of the middle convolution between the axial planes C and D and the crest 17 and trough 18 of the end convolutions, will be gradually flattened. Simultaneously, the

For this purpose they Thusit has been found that with a washer according to the invention a deflection of about three times that of a conventional comparable washer can be obtained for loads between 1000 and 3000 kilograms. It has further been found that in order to obtain best results, the vertices of the wave of the middle convolution should be spaced between 120 and 180.

The desirable large spring movement is accomplished entirely by the provision of the illustrated three turn washer'having a total of about two and three-quarters convolutions, the arcuations of which are formed and relatively arranged as shown and described hereinbefore. In practice it has been found that in the maintenance of railroad trackage, the adherence of the rail to the sleeper of the track when the three turn washer according to the invention is used, decreased at a rate much more retarded than is true when washers previously devised are used, so that a tight connection between the rail and sleeper will be maintained for a proportionally greater length of time, reducing to a marked degree the cost of material and labor expended in track maintenance.

It will be apparent to those skilled in the art that many alterations and modifications of the structure illustrated and hereinbefore described can be made without departure from the essence and spirit of the invention which for that reason shall not be limited but by the scope of the appended claims.

We claim:

1'. A spring washer consisting of a wire rectangular in cross-section and helically coiled so as to formone complete middle convolution and an upper and a lower end convolution, each of a length between three quarters of a coil and a complete coil, the middle convolution being axially bent out of the line of said helix so as to form with its major portion one first wave with the vertex of its crest on the side of said upper end convolution and closely adjacent thereto and the vertex of its trough on the side of said lower end convolution and also closely adjacent thereto, said vertices being equally spaced from the mid-length point of said middle convolution and spaced from each other between and degrees, the remaining portions of said middle convolution together with the adjacent lower and upper end convolutions, respectively, being also wave-like bent out of the line of said helix so that the end points of said middle convolution diametrically opposite said mid-length point are in close proximity to each other, said upper end convolution having a vertex of a wave crest substantially in the same axial plane as the vertex of the trough of said first wave, said lower end convolution having a vertex of a trough substantially in the same axial plane as the vertex of the crest of said first wave, and the end portions of said end convolutions between their ultimate ends and the axial planes of the adjacent vertices, respectively, of said first wave being in close proximitytothe adjacent portions of said middle convolution, whereby said washer has three initial contact points, a first one opposite said mid-length point, and a second and a third one at said vertices, respectively, of said first wave.

2. A spring washer as defined in claim 1 in which the spacing of the middle convolution from each adjacent end convolution between the vertioes of the first wave increases from the axial plane through the vertex near-. est the adjacent end convolution towards the axial plane through the other vertex, first very gradually and then at an increasing rate, whereby said second and third contact points move towards said first one as the compression of the washerincreases once contact has been effected. v

3. A look washer comprising a piece of coil spring having a pair of outer turns and one intermediate turn, each outer turn being provided with two substantially diametrically opposite humps tangent to a plane transverse to the coil axis and forming concavities facing said intermediate turn, a first one of each pair of humps being adjacent-to the free end of the outer turn provided with it; said intermediate turn having diametrically opposite portions deformed into substantial parallelism with said concavities formed by said first humps, the concave sides of said first humps respectively contacting said deformed portions, upon an initial axial compression of said coil spring Without substantial deformation of said humps, over an arc in excess of 4. A lock washer according to claim 3 wherein each .of said humps and deformed portions constitutes the peak of an arched coil segment extending over an angle close to 7

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